1. Field of the Invention
The present invention relates generally to an apparatus for bleaching manufactured white textile fabric items, such as athletic socks, undergarments and the like, prior to their packaging for sale and, more particularly, to a uniquely modified tunnel-type continuous batch washer used to sequentially carry out the various phases of this commercial bleaching process.
2. Description of the Prior Art
In the manufacture of a variety of white textile fabric goods, such as athletic socks, undergarments and the like, it is necessary to bleach the goods before they are packaged for sale since when the fabric goods are initially finished they tend to have a yellowish-gray appearance instead of the bright white color that consumers have become accustomed to over the years. Conventional bleaching processes for these types of white textile fabric goods have traditionally utilized a sodium hypochlorite bleach in one of two types of commercial bleaching machines.
The first type of bleaching machine is commonly referred to as a washer/extractor unit in which all of the bleaching steps, such as bleaching, rinsing and draining, are performed on a stand-alone batch of textile fabric items in a single chamber within the machine. For example, the items are bleached in the chamber; the bleaching liquid is drained from the chamber and replaced with water to rinse the bleached items; the rinse water is drained from the chamber and a softening liquid is added; and the items are finally drained and extracted and transferred to suitable drying apparatus. The washer/extractor unit thus functions quite similarly to a household washing machine, but on a much larger scale. As is well known, this type of bleaching apparatus has an undesirably low batch processing rate, and tends to use an undesirably high quantity of water and chemicals for each pound of textile fabric items being processed.
The other type of machine conventionally used in this bleaching application is commonly referred to as a "paddle tub" machine and comprises an open-topped vat or tub in which bleaching liquid is disposed (and later rinse water) and covers the textile items being bleached. A paddle mechanism disposed above the liquid is driven through an upper portion thereof to create a liquid flow pattern which agitates the items, and enhances the bleaching process, without creating mechanical contact between the paddle structure and the items being bleached. The typical paddle tub machine tends to be relatively expensive, is mechanically complex, and has a relatively slow batch processing rate. Additionally, it has a fairly high water usage rate, typically on the order of 8-15 gallons of water per pound of goods being processed, and a high energy usage rate.
The grandparent application of the present invention was directed to a conventional tunnel-type continuous batch washer which was modified for use as a commercial bleaching machine by (1) lowering the rotational oscillation angle and speed of the machine's inner drum structure relative to its normal washing settings; (2) altering the water counterflow positioning and characteristics; (3) maintaining the water in the various inner drum section modules at essentially identical, relatively high levels; and (4) modifying the bath temperature characteristics of the machine. When utilized as a commercial bleaching machine the modified tunnel washer included a bleach zone disposed at its inlet end and into which a hydrogen peroxide bleaching solution is injected, a finish zone disposed at its outlet end and into which a softening agent is injected, and a water-only rinse zone positioned between the bleach and finish zones. Each of these three zones was defined by one or more inner drum structure modules which may be tandem or single batch modules. While this machine was a dramatic improvement over conventional bleaching ranges, it was found that its performance could even further improved by additions and improvements to its control system. The present invention is based on utilizing the zones in a different manner to provide a prescour zone upstream of the bleaching zone for bleaching more difficult goods.
Thus, there remains a need for a new and improved commercial bleaching apparatus which further eliminates or at least substantially minimizes the above-mentioned problems, limitations and disadvantages commonly associated with conventional bleaching apparatus of the type generally described above.